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digitalmars.D.bugs - [Issue 2076] New: offset doesn't work in asm

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2076

           Summary: offset doesn't work in asm
           Product: D
           Version: 1.028
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: clugdbug yahoo.com.au


I wanted to get the address of a label into a register. This seems to be
impossible at present. I tried various things, including the code below, which
prints:
-----
Error: offset deprecated, use offsetof

which (a) gives no line number; and (b) in the spec, 'offset' is permitted in
asm (and offsetof is not mentioned).
-----

void main()
{
    asm {
        mov EAX, offset L1;
    L1:
    ;
    }
}

Finally,
bug(c):
mov EAX, $; doesn't work either. It seems that $ only works in jmp
instructions?
This is either a compiler bug, or should be mentioned in the spec.

So it seems that there is no way to get the current address into a register.
This limitation means that there's no way to (efficiently) implement duff's
device in asm. But it's probably a side-effect of there being no way to take
the address of a label in normal D code.


--
May 07 2008
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2076


clugdbug yahoo.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|offset doesn't work in asm  |asm: offset has wrong docs
                   |                            |and error without line
                   |                            |number





The inability to get the address of a label is the same bug as 1829.
Changing this to be a documentation bug:
* spec mentions offset, should be offsetof.
* spec mentions seg, which doesn't seem to work (and has no purpose in any
32-bit OS which I know of)
* spec should state that $ only works in jump instructions.

Also has an error without line number. (Note that it would also be possible to
remove the 'offset deprecated' message entirely. It's been years since it was
valid.)


--
Jun 24 2008
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2076


clugdbug yahoo.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED





Fixed DMD1.032


--
Jul 09 2008
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2076






Fixed dmd 2.016


--
Jul 09 2008